Method of performing time-shift function and television receiver using the same

ABSTRACT

A method of performing time-shift function and television receiver having a tuner and a personal video recorder for storing broadcast programs of at least one channel enables a broadcast program of a currently tuned channel to be continuously and efficiently stored to enable time-shifting, regardless of an interruption by switching channels or changing input sources or even in the case of an inadvertent power-off condition. The method includes steps of setting a time-shift lock function; storing in the personal video recorder the broadcast program of a first channel that is currently viewed; storing in the personal video recorder the broadcast program of a second channel and the broadcast program of the first channel, if the currently viewed first channel is switched to the second channel; and supplying power only to the tuner and the personal video recorder, if a power-off condition occurs, wherein the supply of power to the tuner and the personal video recorder causes a continuous storing of the broadcast programs of the first and second channels in the personal video recorder.

This application claims the benefit of Korean Patent Application No.10-2005-0077575, filed on Aug. 24, 2005, which is hereby incorporated byreference as if fully set forth herein.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to television receivers, and moreparticularly, to a television receiver having a personal video recorderand method of storing a broadcast program using the same. Although thepresent invention is suitable for a wide scope of applications, it isparticularly suitable for storing a received broadcast program via apersonal video recorder or PVR enabling a time-shift function.

2. Discussion of the Related Art

A television receiver provided with a personal video recorder includes astorage medium such as a hard disc drive for recording (storing) andreproducing video signals including their associated audio components.The stored signals are digital video signals that are input to thetelevision receiver and may be broadcast signals received from abroadcast station or other signals such as those supplied from aperipheral device connected to the television receiver. In any case, theinput signals are encoded for storage in a transport stream format.

For instance, a television broadcast receiver provided with a personalvideo recorder (PVR) employs a hard disc drive as a storage medium toenable a received broadcast signal or an external input signal from anexternal player to be stored in and reproduced from the hard discaccording to a time-shift function in response to a user selectioninput. Such a time-shift function enables playback functions of pause,reverse play, fast or slow play, and the like for displaying a real-timebroadcast signal or other, similarly received, video stream. Thus, thePVR imparts a television receiver with a time-shift function, whichenables storage of a currently viewed broadcast program selected fromamong multiple available channels and input sources, so that the storedprogram may be subsequently displayed (reproduced) as a time-shiftedprogram according to a user selection.

The time-shift function may be executed by the user at any time, forexample, to immediately or spontaneously replay contents missed whileviewing the broadcast program. Since the time-shift function enables thebroadcast program received via the currently selected channel to bestored, the storage process can be ended by changing the channel or bysimply powering off the television receiver, either of which may beperformed by the user intentionally or unintentionally. Therefore, if auser attempts to view a broadcast program of another channel orotherwise executes a channel changing operation, even momentarily, arecording of the currently viewed broadcast program is interrupted. Indoing so, whenever a program of another channel is viewed, broadcastprograms corresponding to any and all of the switched channels aresequentially stored in the storage medium of the PVR. Consequently, thedesired playback of the originally viewed broadcast program may beimpossible due to an incomplete recording of missed contents. Moreover,if the television receiver is powered off —particularly in the event ofan unintentional action by the user—the time-shift function is ended sothat no playback is possible.

SUMMARY OF THE INVENTION

Accordingly, the present invention is directed to a method of performingtime-shift function and television receiver using the same thatsubstantially obviates one or more problems due to limitations anddisadvantages of the related art.

An object of the present invention is to provide a method of performingtime-shift function and television receiver using the same, by which abroadcast program of a currently tuned channel can be continuously andefficiently stored to enable time-shifting.

Another object of the present invention is to provide a method ofperforming time-shift function and television receiver using the same,by which a broadcast program of a currently tuned channel can becontinuously stored to enable time-shifting in the event of anysubsequent channel changing.

Another object of the present invention is to provide a method ofperforming time-shift function and television receiver using the same,by which a broadcast program of a currently tuned channel can becontinuously stored to enable time-shifting after an unintentionalpowering off of the television receiver.

Additional advantages, objects, and features of the invention will beset forth in part in the description which follows and in part willbecome apparent to those having ordinary skill in the art uponexamination of the following or may be learned from practice of theinvention. The objectives and other advantages of the invention may berealized and attained by the structure particularly pointed out in thewritten description and claims hereof as well as the appended drawings.

To achieve these objects and other advantages in accordance with thepurpose of the invention, as embodied and broadly described herein,there is provided a television receiver comprising a tuner for receivinga broadcast program of at least one channel; a personal video recorderfor storing the received broadcast program of the at least one channel;a user interface for outputting a user command signal for performing atleast one of a power-off operation and a channel switching operation tochange the currently viewed channel from a first channel of the at leastone channel to a second channel of the at least one channel; and acontroller for controlling, according to the user command signal, thepersonal video recorder to store together the broadcast program of thefirst channel and the broadcast program of the second channel.

According to another aspect of the present invention, there is provideda method of performing a time-shift function in a television receiverhaving a tuner and a personal video recorder for storing broadcastprograms of at least one channel. The method comprises storing in thepersonal video recorder the broadcast program of a first channel that iscurrently viewed; and storing in the personal video recorder thebroadcast program of a second channel and the broadcast program of thefirst channel, if the currently viewed first channel is switched to thesecond channel.

It is to be understood that both the foregoing general description andthe following detailed description of the present invention areexemplary and explanatory and are intended to provide furtherexplanation of the invention as claimed.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are included to provide a furtherunderstanding of the invention and are incorporated in and constitute apart of this application, illustrate embodiment(s) of the invention andtogether with the description serve to explain the principle of theinvention. In the drawings:

FIG. 1 is a block diagram of a television receiver according to thepresent invention;

FIG. 2 is a diagram of an OSD screen for selecting modes to perform atime-shift function according to the present invention;

FIG. 3 is a flowchart of a process for storing a broadcast program in atelevision receiver according to the present invention;

FIG. 4 is a diagram of a data storage structure in a storage medium forstoring broadcast programs according to of the present invention; and

FIG. 5 is a flowchart of a process for managing a time-shift storagearea in a television receiver according to the present invention.

DETAILED DESCRIPTION OF THE INVENTION

Reference will now be made in detail to exemplary embodiments of thepresent invention, examples of which are illustrated in the accompanyingdrawings. Wherever possible, like reference designations will be usedthroughout the drawings to refer to the same or similar parts.

Referring to FIG. 1, a television receiver according to the presentinvention includes a tuner 106 for tuning a broadcast program of atleast one channel, the tuner tuning a broadcast program of a firstchannel as a currently viewed channel; a PVR 125 for storing the tunedbroadcast program of the first channel; a user interface 104 foroutputting a command signal input by a user, including a user commandsignal for performing at least one of a power-off operation and achannel switching operation to change the currently viewed channel froma first channel of the at least one channel to a second channel of theat least one channel; and a controller 100 for controlling the broadcastprogram of the first channel and the broadcast program of the secondchannel to be stored together in the PVR for at least a predeterminedtime. According to the user command signal, the controller 100 controlsthe PVR 125 to store in one storage area of a storage medium of the PVRboth the first-channel and the second-channel broadcast programs, whenthe channel switching operation is performed to change the currentlyviewed channel from the first channel to a second channel or when thepower-off operation is performed. The television receiver furtherincludes a system memory 102, an external signal input port 108, avideo/audio signal switch 110, a video memory 114, an MPEG decoder &video/audio signal processor 112, a video signal output circuit 116, adisplay module 118, an audio signal output circuit 120, a speaker 122,and an on-screen display (OSD) generator 127. The PVR 125 includes a PVRcontroller 124 and a storage medium 126 including, for example, a harddisc drive (HDD). The controller 100 controls the respective elements ofthe above television receiver.

According to the present invention, the controller 100 provides atime-shift lock function, which, once set by the user, a broadcastprogram received via a currently viewed channel is continuously storedin the storage medium 126 of the PVR 125 under the control of thecontroller. That is, even if a channel switching or source change takesplace in the course of storing the broadcast program, the controller 100keeps storing in the storage medium 126 of the PVR 125 the broadcastprogram received via the channel or source previously corresponding tothe currently viewed channel as well as the broadcast program of theswitched (new) current channel or the external signal input port 108.Moreover, even if a power-off condition occurs, the controller 100 keepsstoring the broadcast program received the previously current channel bysupplying power only to select elements of the television receiver,namely, the tuner 106, the video/audio signal switch 110, and the PVRcontroller 124 and storage medium 126 of the PVR 125, all of which arerequired for the storage of the broadcast program received via thecurrently viewed channel.

In addition to storing various kinds of information including aprocessing program (system program) of the controller 100, the systemmemory 102 stores under the control of the controller a flag indicatinga setting/release of the time-shift lock function and the data of anelectronic program guide (EPG) recovered from a transport streamcorresponding to the tuned broadcast program. The stored EPG data isused as information for detecting a start time point and an end timepoint of a corresponding broadcast program.

The user interface 104 enables a user to input various command signalsand information to the controller 100. The television receiver may beprovided with one or both of a local keypad and a remote controller tofacilitate the user interface 104.

The tuner 106 tunes at least one channel under the control of thecontroller 100. Thus, a signal received via the tuned at least onechannel is output from the tuner 106 to the video/audio signal switch110 and then on to the MPEG decoder & video/audio signal processor 112.The tuner 106 may be comprised of a single tuner or a plurality oftuners. For example, in the case of channels carrying analog broadcastsignals, a pair of analog signal receiver tuners are needed to tunebroadcast programs from two channels simultaneously, while in the caseof all channels carrying digital broadcast signals, use of a singledigital signal receiving tuner is possible. With a digital signalreceiving tuner, the previously current channel and the switched currentchannel may be logical channels belonging to one physical channel,enabling the signals received via the two channels to be simultaneouslytuned, and respectively stored, using just one tuner. In this case, thetuner 106 recovers a transport stream received via the tuned channelinto an audio stream, a video stream, and a data stream including theEPG data, and the recovered streams are output to the video/audio signalswitch 110 and MPEG decoder & video/audio signal processor 112.

The external signal input port 108 inputs an external signal receivedfrom a peripheral device such as a set-top box, DVD player, orcamcorder. In this case, the received signal is applied to thevideo/audio signal switch 110 in a manner similar to the tuner output.That is, the video/audio signal switch 110 selectively outputs, underthe control of the controller 100, at least one of the signals inputfrom the external signal input port 108 and the tuner 106.

The MPEG decoder & video/audio signal processor 112 recovers the videoand audio streams (i.e., a broadcast signal) of the output signal of thevideo/audio signal switch 110 and converts the recovered signals intovideo and audio signals ready for respective output to the video andaudio signal output circuits 116 and 120, whereby the output videosignal is supplied to the display module 118 and the output audio signalis supplied to the speaker 122. The video memory 114 provides thenecessary memory areas for use by the MPEG decoder & video/audio signalprocessor 112 in decoding and displaying the transport stream. Under thecontrol of the controller 100, the MPEG decoder & video/audio signalprocessor 112 combines the recovered video signal with an OSD datasignal for a superposed display of the combined signal on a screen 118 aof the display module 118. The OSD data signal comprises characters anddiagrammatic information enabling interface between the controller 100and the user, which is generated from the OSD generator 127 under thecontrol of the controller.

The PVR controller 124 stores in the storage medium 126 at least onetransport stream (i.e., video stream and audio stream) output from thevideo/audio signal switch 110. The PVR controller 124 reads the storedtransport stream and outputs the read transport stream to the MPEGdecoder & video/audio signal processor 112, which processes the readvideo and audio streams in the same manner as a received broadcastsignal. The above read/write operations of the PVR 125 are controlled bythe controller 100. Hence, upon a user request, the correspondingbroadcast program stored in the storage medium can be played back, i.e.,reproduced, according to a time-shift function.

According to a method of the present invention, a time-shift function isperformed by a television receiver having a tuner and a personal videorecorder for storing broadcast programs of at least one channel. Themethod includes steps of storing in the personal video recorder thebroadcast program of a first channel that is currently viewed; andstoring in the personal video recorder the broadcast program of a secondchannel and the broadcast program of the first channel, if the currentlyviewed first channel is switched to the second channel according to auser selection.

According to the method of the present invention, to determine whether afirst channel (first-viewed channel) is to be continuously stored, thecontroller 100 preferentially checks whether the first channel has beenviewed and stored for a first predetermined time set for the firstchannel. If the first channel has not been viewed and stored for thefirst predetermined time, the controller 100 stores in the PVR thebroadcast program of the second channel, that is, without storing thebroadcast program of the first channel. Meanwhile, it is similarlynecessary to determine whether the second channel, which is the newchannel (i.e., the channel after a channel changing operation), is to becontinuously stored. The controller 100 therefore determines whetherviewing of the second channel has been maintained for a secondpredetermined time, and if not, the controller stores the broadcastprogram of the first channel only. The first and second channels arerepresentative of the at least one channel of the present invention andmay include a plurality of terrestrial broadcast channels, a pluralityof cable broadcast channels, and channels corresponding to a pluralityof external input sources.

As shown in FIG. 2, showing an exemplary configuration of an OSD screenor menu according to the present invention, the controller 100 displaysan OSD menu on the screen 118 a of the display module 118 according to amenu display request made by the user. The OSD menu may include variousmenu items or icons such as “Channel,” “Video,” “Audio,” “Time,”“Universal,” and hard disc recorder or “HDR.” Here, for example,activation of the universal menu item enables a display and manipulationof submenu items, or icons, relating to general matter such as settingsfor a broadcast guide, a reserved recording, a reservation list, arecording list, a time-shift mode, and a reserved recording quality. Thetime-shift mode includes modes of auto and manual, and correspondingicons are enabled when selecting the time-shift mode.

Importantly, the “Auto” icon of the time-shift mode enables control of atime-shift lock function. That is, by visually referencing the OSD menuand an ON/OFF icon that may be manipulated via the user interface 104,the user is able to turn on (enable) and off (disable) the time-shiftlock function, which is set or released by manipulating the variousicons as described above.

Referring to FIG. 3, illustrating a process for storing a broadcastprogram in a television receiver according to the present invention, thecontroller 100 determines whether the time-shift lock function is set,i.e., on or off (S300). If the time-shift lock function is on (enabled),the controller 100 controls the PVR controller 124 to store in thestorage medium 126 the broadcast program of the currently viewed channel(S302). Otherwise, namely, when the time-shift lock function is off(disabled), the controller 100 executes a corresponding operationaccordingly (S304).

While the broadcast program is being stored, the controller 100determines whether there is an input command from the user, i.e., viathe user interface 104, to turn off power to the televisionreceiver—either intentionally or unintentionally—and thereby disable thetime-shift lock function (S306). If the television receiver is thuspowered off, the controller 100 stops supplying power to a major portionof the television receiver and continues to supply power only to thosetelevision receiver elements that are necessary for performing thetime-shift function (S308). The essential time-shift function elementsmay include the tuner 106, the video/audio signal switch 110, and thePVR 125. In doing so, storage continues for the broadcast program of thecurrently tuned channel being stored in a corresponding time-shiftstorage area of the storage medium 126.

As shown in FIG. 4, the storage medium 126 includes first and secondstorage areas. The second storage area stores the broadcast programsaccording to an execution of the time-shift function, namely, accordingto the time-shift lock function. The first storage area may be used tostore date and time information indicating the time point of storingeach broadcast program as well as to store other general PVR functions.First-through-Nth broadcast programs are stored in the second storagearea.

In storing any one of the broadcast programs, the controller 100 readsan end time point of the broadcast program being stored and stores thecorresponding data in the system memory 102. The end time point isincluded in the EPG data separated from the transport stream of thebroadcast program that is being stored. The end time point is thencompared to a current time point as counted by an internal timer (notshown) of the controller 100, which thereby determines whether theprogram of the current channel has ended (S310). That is, the end of theprogram is recognized if the current time point matches the end timepoint. Then, the controller 100 completes the storage of the broadcastprogram and turns off power to the essential time-shift functionelements (S312).

Meanwhile, if, while the broadcast program is being stored, the userswitches the currently viewed channel to another channel or changes aninput source (S314), the controller 100 determines whether storage ofthe broadcast program of the previous channel was performed in excess ofa predetermined time (S316). Here, the controller 100 is checking to seeif the currently viewed channel is being viewed with interest or whethera user may be performing a channel searching operation or othermomentary channel switching, such that there would be no possibility touse the time-shift function. As in the case of a power-off condition,the channel switching or source change may be as a result of either anintentional or unintentional user action. The predetermined storage timecan be obtained by storing a recording start time point of the broadcastprogram of the corresponding channel and subtracting the recording starttime point from a current time point or can be obtained with referenceto a quantity of the stored broadcast program.

If storage of the broadcast program of the previously current channelexceeds the predetermined time for the time-shift function, thecontroller 100 stores in the storage medium 126 the new broadcastprogram as well as the broadcast program received via the previouslycurrent channel (S318). The new broadcast program may be the program ofthe switched current channel or the program received from the changedinput source. While these broadcast programs are both being stored, thecontroller 100 reads the EPG data stored in the system memory 102, toobtain an end time point of the broadcast program of the previouschannel and thereby determine whether a current time point matches theend time point of the corresponding broadcast program (S320). Upon thusdetermining that the program of the previous channel has ended, thecontroller 100 completes the storage of the broadcast program of theprevious channel (or previously viewed channel) and keeps storing thebroadcast program received from the current (or switched channel) or thechanged input source (S322).

As described above, storage of broadcast programs received from thecurrent and previous channels is only an example, whereby the userperforms the channel switching or changes the input source at least onetime. It is apparent to those skilled in the art that additionalbroadcast programs, namely, programs of the switched channels or fromthe changed input sources, can be continuously and seamlessly stored inthe storage medium. In addition, if the channel switching, input sourcechange, or power-off condition occurs in the course of storing thebroadcast program that is being received via a currently tuned channelor being viewed according to the time-shift function, the broadcastprogram of the previous channel keeps being stored in the storage mediumas well as the broadcast program received via the current channel.Hence, the user is able to seamlessly play back the broadcast program ofthe currently or previously viewed channel according to the time-shiftfunction, even when, either intentionally or unintentionally, executinga series of channel changes or powering off the television receiver.

In a television receiver adopting the present invention, broadcastprograms of any of a plurality of channels may be stored in a storagemedium, whereby a time-shift function can be variously and selectivelyutilized with respect to each stored program. Therefore, a method ofefficiently managing the storage of a plurality of broadcast programs inareas of one storage medium is required.

Referring to FIG. 5, illustrating a process for managing a time-shiftstorage area in a television receiver according to the presentinvention, the controller 100 determines whether storage of a broadcastprogram according to a time-shift function is requested (S500). If suchstorage is requested, the controller 100 determines whether a remainingarea (i.e., the unused portion) of a time-shift storage area of thestorage medium 126 exceeds a predetermined value (S502). If theremaining storage area does not exceed the predetermined value, thecontroller 100 deletes an oldest broadcast program from a plurality ofbroadcast programs stored in the time-shift storage area (S504). Here,the controller 100 is able to search the oldest broadcast program usingdate and time information indicating the time of storing each program,which is stored in the storage medium 126 together the broadcastprograms themselves, as shown in FIG. 4. Once the oldest broadcastprogram is deleted, the controller 100 again determines whether theremaining area of the time-shift storage area of the storage medium 126exceeds the predetermined value (S506), which means there is stillinsufficient unused storage area for performing the requested storage ofthe broadcast program. Deletion of the oldest broadcast program amongthe stored broadcast programs remaining in the time-shift storage areacontinues until freeing sufficient storage area for performing therequested storage operation. That is, if the remaining storage areaexceeds the predetermined value of the step S502 or S506, the controller100 executes the storage of the broadcast program according to thetime-shift function (S508). Meanwhile, without a request for storing abroadcast program according to a time-shift function, the controller 100executes a corresponding operation accordingly (S510).

Embodiments of the present invention include a computer-readable mediumstoring a set of program commands for executing operations implementedby a computer. The computer-readable medium may include the programcommands, a data file, a data structure, and othercomputer-program-related data. The medium and the stored programcommands are configured in accordance with the present invention and maybe specifically designed for the above-described embodiment or maycomprise a device and program combination known to those skilled in thefield of computer software.

By adopting the present invention in a television receiver, while abroadcast program received via a currently viewed channel according to atime-shift function is being stored, storage of the broadcast programcontinues even in the face of an interruption such as changing thechannel or source or powering off the television receiver, therebyenabling a seamless playback of the broadcast program viewed prior tothe interruption. In addition, a storage area can be efficiently managedby storing in one storage medium various broadcast programs receivedfrom a plurality of channels.

It will be apparent to those skilled in the art that variousmodifications can be made in the present invention without departingfrom the spirit or scope of the invention. Thus, it is intended that thepresent invention covers such modifications provided they come withinthe scope of the appended claims and their equivalents.

1. A television receiver, comprising: a tuner for receiving a broadcastprogram of at least one channel, said tuner tuning to a first channel asa currently viewed channel; a personal video recorder for storing thereceived broadcast program of the at least one channel including thefirst channel; a user interface for outputting a user command signal forperforming at least one of a channel switching operation to change thecurrently viewed channel from the first channel to a second channel anda power-off operation; and a controller for controlling, according tothe channel switching operation, said personal video recorder to storetogether both the broadcast program of the first channel and a broadcastprogram of the second channel, and if the user command for performingthe power-off operation is output, the controller supplies power only tothe tuner and the personal video recorder to continually store thereceived broadcast program of the first channel.
 2. The televisionreceiver of claim 1, wherein the at least one channel includes aplurality of terrestrial broadcast channels, a plurality of cablebroadcast channels, and channels corresponding to a plurality ofexternal input sources.
 3. The television receiver of claim 1, wherein,in performing the power-off operation, said controller stops supplyingpower to components of the receiver that are not necessary forperforming the time-shift function.
 4. The television receiver of claim1, wherein, in performing the channel switching operation, the broadcastprogram of the first channel is stored in the personal video recorderuntil the broadcast program of the first channel ends.
 5. The televisionreceiver of claim 1, wherein the controller determines whether thebroadcast program of the first channel has been viewed and stored for atleast a first predetermined time, and if the first channel has not beenviewed and stored for at least the first predetermined time, thecontroller controls the personal video recorder to store the broadcastprogram of the second channel and not to store the broadcast program ofthe first channel.
 6. A method of performing a time-shift function in atelevision receiver having a tuner and a personal video recorder forstoring broadcast programs of at least one channel, the methodcomprising: storing in the personal video recorder the broadcast programof the at least one channel including a first channel that is currentlyviewed; storing in the personal video recorder the broadcast program ofa second channel and the broadcast program of the first channel, if thecurrently viewed first channel is switched to the second channel;receiving a command for performing a power-off operation; and supplyingpower only to the tuner and the personal video recorder to continuallystore the received broadcast program of the first channel.
 7. The methodof claim 6, further comprising: determining whether the broadcastprogram of the first channel has been viewed and stored at least for afirst predetermined time; and storing, if the first channel has not beenviewed and stored at least for the first predetermined time, thebroadcast program of the second channel in the personal video recorder,the broadcast program of the first channel not being stored in thepersonal video recorder.
 8. The method of claim 6, further comprising:determining whether the second channel is maintained without channelswitching for a second predetermined time; and storing, if the secondchannel is not maintained for the second predetermined time, thebroadcast program of the first channel in the personal video recorder,the broadcast program of the second channel not being stored in thepersonal video recorder.
 9. The method of claim 6, wherein, inperforming the channel switching operation, the broadcast program of thefirst channel is stored in the personal video recorder until thebroadcast program of the first channel ends.
 10. The method of claim 6,further comprising: setting a time-shift lock function.
 11. The methodof claim 10, wherein said supply of power to the tuner and the personalvideo recorder causes a continuous storing of the broadcast programs ofthe first and second channels in the personal video recorder.
 12. Themethod of claim 6, wherein the at least one channel includes a pluralityof terrestrial broadcast channels, a plurality of cable broadcastchannels, and channels corresponding to a plurality of external inputsources.
 13. The method of claim 6, further comprising: (a) determiningwhether a storage of at least one of the broadcast programs is requestedaccording to the time-shift function; (b) determining, if the storage ofat least one of the broadcast programs is requested, whether sufficientunused storage area of within the personal video recorder is present;(c) deleting, if insufficient unused storage area of within the personalvideo recorder is present, an oldest of the stored broadcast programsbased on time of storage; and (d) repeating said steps b and c untilsufficient unused storage area of within the personal video recorder ispresent.
 14. The method of claim 13, further comprising: storing in thepersonal video recorder the at least one of the broadcast programsrequested according to the time-shift function.
 15. The method of claim6, further comprising: determining whether a storage of at least one ofthe broadcast programs is requested according to the time-shiftfunction; determining, if the storage of the at least one of thebroadcast programs is requested, whether an unused portion of atime-shift storage area of a storage medium within the personal videorecorder exceeds a predetermined value; repeatedly deleting, if theunused area of the time-shift storage area does not exceed thepredetermined value, an oldest program among the broadcast programsstored in the time-shift storage area until, said repeated deletioncontinuing until the unused area of the time-shift storage area exceedsthe predetermined value; and storing in the personal video recorder theat least one of the broadcast programs requested according to thetime-shift function, if the unused area exceeds the predetermined value.